1. Field of the Invention
The present invention relates to a stator for an inner rotor type mold brushless motor.
2. Description of the Related Art
As a conventional type of brushless motor, so-called inner rotor type brushless motor in which a rotor is provided inside a stator that generates a magnetic field has been known. In this type of brushless motor, a plurality of teeth protrude toward the inside of the cylindrical stator. Each tooth includes a coil. Inside the stator is provided a rotor having a multipolar magnet. This rotor is rotated by means of the magnetic filed of the stator.
A brushless motor described in JP H9 (1997)-191588 A is provided with a stator including the combination of a plurality of iron core pieces, each corresponding to a tooth, arranged like a circle. To each iron core piece is attached a coil form made of synthetic resin. The coil form is for winding a coil therearound. The outer diameter side of the coil form is provided with a plurality of stages of grooves for holding a bridge line. These grooves are orthogonal to the axis direction of the brushless motor. The respective stages of grooves are formed stepwise, in which a bridge line is held.
In the above mentioned stator, the coil form is provided with the plurality of stages of grooves formed stepwise for holding the bridge line, and the bridge line is placed in the grooves while being bent. Thus, the bridge line may get damaged when it is placed in the grooves.
A brushless motor described in JP 2002-34212 A is provided with a stator composed of twelve split stators. Each split stator includes an iron core piece, a tooth and an insulator provided integrally therewith made of an insulating material. In this insulator, a vertical groove parallel to the axis direction of the motor and a horizontal groove orthogonal to the axis direction are formed. All of the split stators are arranged like a circle, so that bridge lines are placed in the respective stages of the horizontal grooves via the vertical grooves, thus establishing mutual insulation.
In the above mentioned split stators, since the vertical grooves are continuous with all of the horizontal grooves of the brushless motor, a nozzle of a winding machine needs to be driven at a predetermined position of the horizontal grooves precisely.
In addition, in conventional mold brushless motors, when a stator is molded with resin, bridge lines may be displaced due to the pressure of the resin. As a result, the bridge lines may contact with each other, thus causing an electrical short.